The Maori Council's claim over water at the Waitangi Tribunal is "opportunistic" and there should be no link made to the Mighty River share sale, Prime Minister John Key says.

However, Labour leader David Shearer today said the Government had to consider delaying the share sale as it had become a shambles.

Speaking to reporters before the National Party's caucus meeting, Key said if the matter of Maori water rights was taken to court, after the tribunal made its recommendations, it would be a complex issue.

He assumed it would be a move to slow down and stop the process until water rights and interests were better defined.

"The Crown sees no merit in that argument. … we do not believe there's any link between the sale of share in Mighty River Power and whatever rights or interests Maori might have in water."

He repeated he could see no reason why the Maori Party would pull its support from the Government over the statements he has made, which included that the tribunal's recommendations were not binding and that no-one owned water.

He took the Council's claim as one for ownership of water, not just rights and interests.

"The Maori Council are essentially saying, … as articulated by Maanu Paul when he said they own the water, that ownership means any change in the ownership structure of Mighty River."

That would therefore be impacted by a potential change in ownership.

"The Crown's long held view is that it's irrelevant whether there is a change of ownership structure in Mighty River Power, it has no bearing to any rights or interests in water that Mighty River Power currently has long term water rights for."

He would not confirm the sale of Mighty River Power would be delayed till next year by a court challenge.

"There's a chance a meteorite will hit the Earth this afternoon, but I don't think it's likely."

The courts had in the past stopped the Government progressing its policies where issues involved a direct interest in land.

"But where more tangential arguments are brought up around rights and interests, then the courts don't have a history of stopping governments."

Asked whether potential investors should be worried about Maori claims over water, he noted that many companies dealt with water rights, including listed Contact Energy, and he had seen no movement in their share prices because of what was going on at the moment.

Shearer said Key had to look at delaying the sale of Mighty River Power.

The process had become a "complete shambles", he told reporters.

"The sale will probably have to be delayed and the share price will be affected. There will be issues around costs and who will meet those costs, it's going to be the taxpayer."

New Zealanders wanted the best share price they could possibly get for their assets, Shearer said.

"With the uncertainty and the risk around this, that is very questionable."

Key was "trying to talk up" the process by saying there was nothing wrong.

"I think just about every New Zealander looking at this can see this is a complete train wreck."

'NEGOTIATE WATER DIRECTLY'

Prime Minister John Key says negotiating directly with the Government is a ''much more logical and sensible way'' for Maori to resolve water rights issues than through the Waitangi Tribunal.

Maori had achieved good outcomes over the Waikato River, Taniwha Springs in Rotorua and more recently at Tahuna, he said.

''The Government's view is that is the right process, it's been the most successful," he told TV3's Firstline programme.

The Prime Minister has been heavily criticised for his attitude towards the tribunal hearing after saying the Government could ignore its ruling. He has since stressed the Government would listen in good faith.

There is growing pressure on the Maori Party to walk away from its support agreement with the Government over Key's comments. Key is expected to meet co-leaders Pita Sharples and Tariana Turia tomorrow over the issue.

Key today rejected suggestions of growing pressure and speculation the issue was escalating into the furore created with the foreshore and seabed law which Turia walked out of Labour over.

''I think that's nonsense,'' Key said.

Those calling for the Maori Party to walk away were mainly lawyer and Mana Party member Annette Sykes and Maori Council chair Manu Paul who were ''largely supporters of (Mana Party leader) Hone Harawira'', he said.

''That does not mean that the Maori Party should leave. I think they've achieved an awful lot in Government.''

The Maori Council only represented one group within Maoridom, Key said.

''It's not necessarily the view shared by many other groups within Maoridom.''

Key said he couldn't rule out the sale of Might River Power being delayed by likely subsequent court action by the Maori Council.